Schematics of the human astrovirus type 1 (HAstV-1) genome organization, showing the RNA-dependent RNA polymerase knockout (RdRp ko) site used to generate a replication-incompetent control mutant from the wild type (wt) (a) and the HAstV-1 virus rescue system (b). (c) Schematics of the HAstV-1 dual-reporter replicons. Two nonlabeled arrows pointing to regions in the ORF1a where the first 45 nt of the ORF1a are placed twice. iv, in vitro; UTR, untranslated region; ORF, open reading frame; VPg, viral protein linked to the genome; GFP, green fluorescent protein; nluc, nanoluciferase; fluc, firefly luciferase.